cmake support set iOS Deployment Target for root project (cocos2d#19315)

* support set ios deployment target for root project

* update gitignore

Author: drelaptop

.gitignore

@@ -166,3 +166,19 @@ tests/lua-tests/project/proj.tizen/res/
 *-build/
 # Ignore the CLion build folder, such as cmake-build-debug
 cmake-build-*/
+.vs
+cmake_build*
+
+# tmp android build files
+cocos/platform/android/libcocos2dx/.project
+tests/lua-tests/project/proj.android/.project
+tests/lua-tests/project/proj.android/app/.project
+tests/*/proj.android/.settings/org.eclipse.buildship.core.prefs
+tests/*/project/proj.android/.settings/org.eclipse.buildship.core.prefs
+
+# tmp folder for temp usage
+tmp/
+temp/
+
+# external libs zip
+*.zip

cmake/ios.toolchain.cmake

@@ -35,8 +35,9 @@ set(UNIX True)
 set(APPLE True)
 set(IOS True)
 
-# Required as of cmake 2.8.10
-set(CMAKE_OSX_DEPLOYMENT_TARGET "" CACHE STRING "Force unset of the deployment target for iOS" FORCE)
+# support iOS on cmake 3.11+
+# cmake 3.11 milestone feature, https://gitlab.kitware.com/cmake/cmake/issues/17431 
+set(CMAKE_OSX_DEPLOYMENT_TARGET "8.0" CACHE STRING "set of the deployment target for iOS" FORCE)
 
 # Determine the cmake host system version so we know where to find the iOS SDKs
 find_program(CMAKE_UNAME uname /bin /usr/bin /usr/local/bin)